Seamless steel tube for boiler

Abstract

The utility model discloses a seamless steel pipe for a boiler. The seamless steel pipe comprises a pipe body, a composite coating, reinforcing ribs, an elastic supporting piece and a protective shell. The inner wall of the pipe body is provided with a multi-layer composite coating which is composed of a corrosion-resistant layer, an anti-oxidation layer and a heat conduction enhancement layer, so that the corrosion resistance, the oxidation resistance and the heat conduction performance are improved; reinforcing ribs and radiating grooves are arranged on the outer wall of the tube body, so that the structural strength and the radiating efficiency are enhanced; the protective shell is connected with the pipe body through an elastic supporting piece, and the protective shell absorbs alternating stress and adapts to expansion deformation. And the protective shell is provided with vent holes and arc-shaped grooves, so that heat dissipation and stress dispersion are optimized. The utility model solves the problems of oxide layer stripping, heat conduction efficiency reduction and fatigue damage in a high-temperature environment, obviously improves the operation efficiency of the boiler and prolongs the service life of the steel pipe.

Description

Technical Field

[0001] This utility model relates to the field of boiler and pipe material technology, and in particular to a seamless steel pipe for boilers. Background Technology

[0002] Seamless steel pipes are widely used in boiler equipment in high-temperature and high-pressure working environments, and their performance directly affects the boiler's operating efficiency and safety. For boiler systems, seamless steel pipes not only need to have high strength and corrosion resistance, but also need to be able to withstand thermal stress changes under extreme conditions, which is particularly important for ensuring the long-term stable operation of the boiler.

[0003] Due to the complex operating environment of boilers, seamless steel pipes face challenges such as high-temperature oxidation and internal pressure fluctuations during use. Existing seamless steel pipes primarily improve performance through optimized material composition and manufacturing processes, but certain limitations remain in practical applications. For example, under prolonged high-temperature conditions, the oxide layer on the inner wall of the pipe is prone to peeling off, which not only affects heat transfer efficiency but may also cause localized blockages. Furthermore, steel pipes may experience fatigue damage under alternating stress, thus shortening their service life. Therefore, how to further improve the overall performance of seamless steel pipes has become a crucial issue in the current boiler technology field. Utility Model Content

[0004] The purpose of this utility model is to provide a seamless steel pipe for boilers, which solves the problems mentioned in the background art.

[0005] This utility model is implemented as follows: a seamless steel pipe for boilers includes a pipe body with multiple axially extending reinforcing ribs on its outer wall, forming heat dissipation grooves between adjacent reinforcing ribs. The inner wall surface of the pipe body is coated with a multi-layer composite coating, consisting of a corrosion-resistant layer, an oxidation-resistant layer, and a thermally conductive enhancement layer from the inside out. It also includes a protective shell nested outside the pipe body, connected to the pipe body by multiple spaced elastic supports. These elastic supports are evenly arranged radially along the pipe body, with one end fixed to a reinforcing rib on the outer wall of the pipe body and the other end fixed to the inner wall of the protective shell. Multiple vent holes are provided on the outer wall of the protective shell, corresponding to the positions of the heat dissipation grooves.

[0006] Furthermore, the reinforcing rib has a trapezoidal cross-section, with its top width being smaller than its bottom width, and its top surface is polished to reduce stress concentration. The height of the reinforcing rib is 1 / 10 to 1 / 8 of the outer diameter of the tube, and the spacing between adjacent reinforcing ribs is 1 / 5 to 1 / 4 of the outer diameter of the tube, to ensure that the heat dissipation groove has sufficient heat dissipation area without affecting the overall strength of the tube.

[0007] Furthermore, the corrosion-resistant layer in the composite coating is made of nickel-based alloy material with a thickness of 0.1 mm to 0.2 mm, mainly used to resist chemical corrosion under high temperature environment; the anti-oxidation layer is made of ceramic matrix composite material with a thickness of 0.2 mm to 0.3 mm, used to prevent the peeling of the inner wall oxide layer; the thermal conductivity enhancement layer is made of graphene-based composite material with a thickness of 0.05 mm to 0.1 mm, used to improve the thermal conductivity efficiency of the inner wall.

[0008] Furthermore, the elastic support is made of spring steel, and its two ends are fixed to the outer wall of the tube and the inner wall of the protective shell by threaded connection. The length of the elastic support is 1 / 6 to 1 / 5 of the outer diameter of the tube, and its elastic modulus has been calculated and designed to accommodate the expansion and deformation of the tube under high temperature and high pressure environment, and to absorb part of the alternating stress, thereby reducing the risk of fatigue damage.

[0009] Furthermore, the inner wall of the protective shell is provided with multiple circumferentially distributed arc-shaped grooves. The positions of the arc-shaped grooves correspond to the distribution positions of the elastic support members, and the depth of the arc-shaped grooves is 1 / 3 to 1 / 2 of the wall thickness of the protective shell. The design of the arc-shaped grooves can effectively disperse the stress transmitted by the elastic support members and avoid stress concentration causing damage to the protective shell.

[0010] Furthermore, the vent is elliptical in shape, with its major axis parallel to the axial direction of the protective housing and its minor axis parallel to the radial direction of the protective housing. The length of the major axis of the vent is 1 / 10 to 1 / 8 of the outer diameter of the protective housing, and the length of the minor axis is 1 / 20 to 1 / 15 of the outer diameter of the protective housing, to ensure smooth airflow while preventing external impurities from entering the interior of the protective housing.

[0011] Furthermore, flanges are provided at both ends of the pipe body. Multiple evenly distributed mounting holes are formed on the outer edge of the flanges, with a diameter of 10mm to 15mm and a spacing between adjacent mounting holes of 1 / 6 to 1 / 5 of the flange's outer diameter. A sealing ring groove is provided on the inner side of the flange, and a high-temperature resistant sealing ring is embedded within the sealing ring groove to ensure sealing performance when the pipe body is connected to other components.

[0012] Furthermore, annular baffles are respectively provided at both ends of the protective shell. The annular baffles are fixed to the inner wall of the protective shell by welding, and the inner diameter of the annular baffles is slightly larger than the outer diameter of the tube to form a clearance fit. The function of the annular baffles is to limit the axial displacement of the elastic support and prevent external impurities from entering the interior of the protective shell.

[0013] The seamless steel pipe for boilers provided by this utility model has the following beneficial effects:

[0014] Firstly, by applying a multi-layer composite coating to the inner wall of the pipe, the synergistic effect of the corrosion-resistant layer, anti-oxidation layer, and thermal conductivity enhancement layer solves the problem of oxide layer peeling and reduced heat transfer efficiency in traditional seamless steel pipes under high-temperature environments. The corrosion-resistant layer effectively resists chemical corrosion, the anti-oxidation layer prevents oxide layer peeling, and the thermal conductivity enhancement layer significantly improves heat transfer efficiency, thereby enhancing the overall operating efficiency of the boiler.

[0015] Secondly, by setting reinforcing ribs on the outer wall of the pipe and installing elastic supports between the reinforcing ribs and the protective shell, the problem of fatigue damage easily occurring in traditional seamless steel pipes under alternating stress is solved. The reinforcing ribs not only enhance the structural strength of the pipe but also improve heat dissipation performance through the design of heat dissipation grooves; the elastic supports can absorb some of the alternating stress and adapt to the expansion and deformation of the pipe under high-temperature environments, thereby extending the service life of the steel pipe.

[0016] Finally, by incorporating vents and arc-shaped grooves on the protective shell, the problem of insufficient heat dissipation performance of traditional seamless steel pipes in high-temperature environments was solved. The combined design of the vents and heat dissipation grooves effectively improves heat dissipation efficiency, while the arc-shaped grooves disperse the stress transmitted by the elastic support components, preventing stress concentration from damaging the protective shell, thereby further enhancing the overall performance of the steel pipe.

[0017] In summary, this utility model achieves a comprehensive improvement in the performance of seamless steel pipes by using specific technical means such as setting a multi-layer composite coating on the inner wall of the pipe, setting reinforcing ribs and elastic support components on the outer wall of the pipe, and setting vent holes and arc-shaped grooves on the protective shell. It solves the problems of oxide layer peeling, reduced heat conduction efficiency and fatigue damage existing in the prior art, and has significant technical advantages and practicality. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the present invention, showing the arrangement of the seamless steel pipe body, reinforcing ribs, protective shell and elastic support. The reinforcing ribs extend along the axial direction of the pipe body, the heat dissipation grooves are located between adjacent reinforcing ribs, and the protective shell is connected to the pipe body through the elastic support.

[0019] Figure 2 This utility model Figure 1 A partial disassembly diagram.

[0020] Figure 3 This utility model Figure 2 Enlarged view of point A.

[0021] The attached diagram is labeled as follows: 1. Pipe body; 2. Reinforcing rib; 3. Heat dissipation groove; 4. Composite coating; 5. Corrosion-resistant layer; 6. Anti-oxidation layer; 7. Thermally conductive enhancement layer; 8. Protective shell; 9. Elastic support; 10. Vent hole; 11. Arc-shaped groove; 12. Flange; 13. Annular baffle. Detailed Implementation

[0022] This utility model provides a seamless steel pipe for boilers, the overall structure of which is as follows: Figure 1 As shown, the structure includes a tube body 1, reinforcing ribs 2, a protective shell 8, and elastic support members 9. The tube body 1, as the core component, has multiple reinforcing ribs 2 arranged axially on its outer wall. Heat dissipation grooves 3 are formed between adjacent reinforcing ribs 2. The design of these heat dissipation grooves 3 not only effectively improves heat dissipation performance but also ensures that the overall strength of the tube body 1 is not weakened. The cross-section of the reinforcing ribs 2 is trapezoidal, with the top width smaller than the bottom width, and the top is polished to reduce stress concentration. The height of the reinforcing ribs 2 is 1 / 10 to 1 / 8 of the outer diameter of the tube body 1, and the spacing between adjacent reinforcing ribs 2 is 1 / 5 to 1 / 4 of the outer diameter of the tube body 1. This dimensional design ensures that the heat dissipation grooves 3 have sufficient heat dissipation area without negatively impacting the structural strength of the tube body 1.

[0023] The inner wall surface of the pipe body 1 is provided with a multi-layer composite coating 4, such as Figure 2 As shown, the composite coating 4 consists of a corrosion-resistant layer 5, an anti-oxidation layer 6, and a thermally conductive reinforcing layer 7, from the inside out. The corrosion-resistant layer 5 is made of a nickel-based alloy with a thickness of 0.1 mm to 0.2 mm, and its main function is to resist chemical corrosion under high-temperature environments. The anti-oxidation layer 6 is made of a ceramic-based composite material with a thickness of 0.2 mm to 0.3 mm, and its main function is to prevent the oxide layer on the inner wall from peeling off. The thermally conductive reinforcing layer 7 is made of a graphene-based composite material with a thickness of 0.05 mm to 0.1 mm, and its function is to improve the heat transfer efficiency of the inner wall. These three composite coating layers 4 are sequentially applied to the inner wall of the pipe body 1 through spraying or electroplating processes. Each layer is firmly bonded together by an interface binder, thus forming a complete protective system.

[0024] A protective shell 8 is nested inside the tube body 1. The protective shell 8 is connected to the tube body 1 by multiple spaced-apart elastic support members 9, such as... Figure 3As shown. Elastic supports 9 are evenly arranged radially along the tube body 1. One end of each elastic support 9 is fixed to a reinforcing rib 2 on the outer wall of the tube body 1, and the other end is fixed to the inner wall of the protective shell 8. The elastic supports 9 are made of spring steel, and both ends are fixed by threaded connections. Their length is 1 / 6 to 1 / 5 of the outer diameter of the tube body 1. The design of the elastic supports 9 is precisely calculated; their elastic modulus can accommodate the expansion and deformation of the tube body 1 under high temperature and high pressure, while absorbing some alternating stress, thereby reducing the risk of fatigue damage. Multiple circumferentially distributed arc-shaped grooves 11 are provided on the inner wall of the protective shell 8. The positions of the arc-shaped grooves 11 correspond to the distribution positions of the elastic supports 9, and the depth of the arc-shaped grooves 11 is 1 / 3 to 1 / 2 of the wall thickness of the protective shell 8. The design of the arc-shaped grooves 11 can effectively disperse the stress transmitted by the elastic supports 9, avoiding stress concentration that could damage the protective shell 8.

[0025] Multiple vent holes 10 are provided on the outer wall of the protective housing 8, corresponding to the positions of the heat dissipation grooves 3. The vent holes 10 are elliptical in shape, with their major axis parallel to the axial direction of the protective housing 8 and their minor axis parallel to the radial direction of the protective housing 8. The length of the major axis of the vent hole 10 is 1 / 10 to 1 / 8 of the outer diameter of the protective housing 8, and the length of the minor axis is 1 / 20 to 1 / 15 of the outer diameter of the protective housing 8. This design ensures smooth airflow while preventing external impurities from entering the interior of the protective housing 8. Flanges 12 are provided at both ends of the pipe body 1. Multiple evenly distributed mounting holes are provided on the outer edge of the flanges 12, with a diameter of 10mm to 15mm and a spacing between adjacent mounting holes of 1 / 6 to 1 / 5 of the outer diameter of the flange 12. A sealing ring groove is provided on the inner side of the flange 12, and a high-temperature resistant sealing ring is embedded in the sealing ring groove to ensure the sealing performance when the pipe body 1 is connected to other components.

[0026] Annular baffles 13 are respectively provided at both ends of the protective shell 8. The annular baffles 13 are fixed to the inner wall of the protective shell 8 by welding, and the inner diameter of the annular baffles 13 is slightly larger than the outer diameter of the pipe body 1 to form a clearance fit. The function of the annular baffles 13 is to limit the axial displacement of the elastic support 9 and prevent external impurities from entering the interior of the protective shell 8. This design not only enhances the sealing performance of the protective shell 8, but also further improves the stability and reliability of the entire seamless steel pipe.

[0027] In practical applications, the seamless steel pipe of this invention is widely used in industrial boiler equipment, especially exhibiting excellent performance in high-temperature and high-pressure working environments. When the boiler is running, high-temperature and high-pressure steam or water flows inside the pipe body 1, at which time the multi-layer composite coating 4 on the inner wall of the pipe body begins to play its role. The corrosion-resistant layer 5 first resists chemical corrosion under high-temperature conditions, preventing the inner wall of the pipe body from being eroded; the anti-oxidation layer 6 prevents the inner wall oxide layer from peeling off, avoiding local blockage problems caused by oxide layer peeling off; the thermal conductivity enhancement layer 7 significantly improves the heat transfer efficiency of the inner wall, thereby improving the overall operating efficiency of the boiler. At the same time, the reinforcing ribs 2 on the outer wall of the pipe body 1 quickly dissipate heat to the external environment through the heat dissipation grooves 3, further reducing the temperature of the pipe body 1, thereby reducing the impact of thermal stress.

[0028] During boiler operation, the tube body 1 is subjected to alternating stress due to frequent internal pressure fluctuations. At this time, the elastic support 9 absorbs some of the alternating stress through its elastic properties, while also adapting to the expansion and deformation of the tube body 1 under high-temperature conditions, thereby reducing the risk of fatigue damage. The arc-shaped groove 11 design of the protective shell 8 effectively disperses the stress transmitted by the elastic support 9, preventing stress concentration from damaging the protective shell 8. Furthermore, the coordinated design of the vent holes 10 and heat dissipation grooves 3 on the protective shell 8 further improves heat dissipation efficiency, ensuring that the tube body 1 maintains stable performance under high-temperature conditions.

[0029] The design of flange 12 allows the seamless steel pipe to be easily connected to other components, the even distribution of mounting holes ensures the stability of the connection, and the high-temperature resistant sealing ring in the sealing ring groove guarantees the sealing performance of the connection. The annular baffle 13 restricts the axial displacement of the elastic support 9 through clearance fit, while preventing external impurities from entering the protective shell 8, thereby improving the reliability and service life of the entire seamless steel pipe.

[0030] This invention achieves a comprehensive improvement in the performance of seamless steel pipes through the above-described specific embodiments, and solves problems such as oxide layer peeling, reduced heat conduction efficiency, and fatigue damage existing in the prior art. It has significant technical advantages and practicality.

[0031] To enable those skilled in the art to fully understand and implement this utility model, the specific implementation principle of this utility model is further supplemented below with a specific application scenario.

[0032] In the actual operation of boiler equipment, seamless steel pipes are widely used as core heat transfer components in high-temperature and high-pressure environments. When the boiler starts, high-temperature and high-pressure steam or water begins to flow inside the pipe body 1. At this time, the multi-layer composite coating 4 on the inner wall of the pipe body 1 gradually comes into play. First, the corrosion-resistant layer 5, through the properties of its nickel-based alloy material, resists the erosion of chemical media under high-temperature conditions, preventing damage to the inner wall of the pipe body from long-term contact with corrosive substances. The anti-oxidation layer 6 utilizes the high stability and density of the ceramic matrix composite material to form a robust protective barrier under high-temperature conditions, preventing the oxide layer from peeling off. The thermal conductivity enhancement layer 7, based on graphene-based composite material, rapidly transfers heat to the outer wall of the pipe body 1 through its excellent thermal conductivity, thereby improving the overall heat transfer efficiency. These composite coatings 4 are sequentially applied to the inner wall of the pipe body 1 through spraying or electroplating processes and are firmly connected through an interface binder, ensuring the synergistic effect of each layer under complex operating conditions.

[0033] Meanwhile, the reinforcing ribs 2 on the outer wall of the tube body 1 and the heat dissipation grooves 3 work together to improve heat dissipation performance. The reinforcing ribs 2 extend axially along the tube body 1, and their trapezoidal cross-section structure is precisely designed, with the top width smaller than the bottom width and polished, effectively reducing stress concentration. The heat dissipation grooves 3 between adjacent reinforcing ribs 2 provide an efficient heat dissipation channel. When high-temperature steam or water flows through the tube body 1, heat is transferred outward through the inner wall of the tube body 1 to the reinforcing ribs 2, and then rapidly dissipated into the external environment through the heat dissipation grooves 3. This design not only significantly reduces the overall temperature of the tube body 1 but also reduces the risk of deformation caused by changes in thermal stress, thus ensuring the stability of the tube body 1 during long-term operation.

[0034] During boiler operation, frequent internal pressure fluctuations inevitably subject the tube body 1 to alternating stress. At this time, the design of the elastic support 9 plays a crucial role. The elastic support 9 is made of spring steel, with its two ends fixed to the reinforcing ribs 2 on the outer wall of the tube body 1 and the inner wall of the protective shell 8, respectively. Its length is 1 / 6 to 1 / 5 of the outer diameter of the tube body 1. When the tube body 1 deforms due to high-temperature expansion or pressure fluctuations, the elastic support 9 can absorb part of the alternating stress through its elastic properties, while also adapting to the expansion and deformation of the tube body 1. This design not only reduces the risk of fatigue damage to the tube body 1 caused by alternating stress but also enhances the deformation resistance of the entire seamless steel pipe. Furthermore, the arc-shaped groove 11 on the inner wall of the protective shell 8 further disperses the stress transmitted by the elastic support 9, preventing potential damage to the protective shell 8 caused by stress concentration.

[0035] The vents 10 on the outer wall of the protective housing 8 correspond to the positions of the heat dissipation grooves 3, forming a highly efficient heat dissipation system. The elliptical design of the vents 10 ensures smooth airflow while preventing external impurities from entering the interior of the protective housing 8. When heat is dissipated from the heat dissipation grooves 3 to the area around the protective housing 8, the vents 10 guide external cool air in and exchange heat with the surface of the protective housing 8, thereby further reducing the temperature of the tube 1. This combined design significantly improves heat dissipation efficiency, ensuring that the tube 1 maintains stable performance even under high temperature and high pressure environments.

[0036] The design of flange 12 allows for easy connection of the seamless steel pipe to other boiler components. The evenly distributed mounting holes on the outer edge of flange 12 ensure a stable connection; the high-temperature resistant sealing ring embedded in the sealing ring groove guarantees the sealing performance at the connection, preventing leakage of high-temperature and high-pressure media. The annular baffles 13 at both ends of the protective shell 8 are fixed to the inner wall of the protective shell 8 by welding. Their inner diameter is slightly larger than the outer diameter of the pipe body 1, forming a clearance fit. The annular baffles 13 not only restrict the axial displacement of the elastic support 9 but also effectively prevent external impurities from entering the interior of the protective shell 8, thereby further improving the reliability and service life of the entire seamless steel pipe.

[0037] In summary, this utility model achieves efficient operation of seamless steel pipes under high temperature and high pressure environments through the specific implementation steps described above. Whether it's the multi-layer composite coating 4 on the inner wall of the pipe body 1, the reinforcing ribs 2 and heat dissipation grooves 3 on the outer wall, or the synergistic effect of the elastic support 9 and the protective shell 8, all these aspects address the problems existing in the prior art from different perspectives. This design is practical and feasible, significantly improving the overall performance of seamless steel pipes and possessing significant practical application value.

[0038] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A seamless steel pipe for boilers, comprising a pipe body (1), characterized in that: The outer wall of the tube body (1) is provided with a plurality of axially extending reinforcing ribs (2), and heat dissipation grooves (3) are formed between adjacent reinforcing ribs (2). The inner wall surface of the tube body (1) is provided with a multi-layer composite coating (4). The composite coating (4) consists of a corrosion-resistant layer (5), an anti-oxidation layer (6), and a thermally conductive enhancement layer (7) from the inside to the outside. It also includes a protective shell (8) nested outside the tube body (1). The protective shell (8) is connected to the tube body (1) by a plurality of spaced elastic support members (9). The elastic support members (9) are evenly arranged along the radial direction of the tube body (1), and one end of each elastic support member (9) is fixed to the reinforcing rib (2) on the outer wall of the tube body (1), and the other end is fixed to the inner wall of the protective shell (8). A plurality of vent holes (10) are provided on the outer wall of the protective shell (8), and the vent holes (10) correspond to the positions of the heat dissipation grooves (3).

2. A seamless steel pipe for boilers according to claim 1, characterized in that: The cross-section of the reinforcing rib (2) is trapezoidal, with its top width being smaller than its bottom width, and its top surface is polished. The height of the reinforcing rib (2) is one-tenth to one-eighth of the outer diameter of the tube body (1), and the spacing between adjacent reinforcing ribs (2) is one-fifth to one-quarter of the outer diameter of the tube body (1).

3. A seamless steel pipe for boilers according to claim 1, characterized in that: The corrosion-resistant layer (5) in the composite coating (4) is made of nickel-based alloy material with a thickness of 0.1 mm to 0.2 mm, the anti-oxidation layer (6) is made of ceramic matrix composite material with a thickness of 0.2 mm to 0.3 mm, and the thermally conductive reinforcement layer (7) is made of graphene-based composite material with a thickness of 0.05 mm to 0.1 mm.

4. A seamless steel pipe for boilers according to claim 1, characterized in that: The elastic support (9) is made of spring steel and its two ends are fixed to the outer wall of the tube (1) and the inner wall of the protective shell (8) by means of threaded connection. The length of the elastic support (9) is one-sixth to one-fifth of the outer diameter of the tube (1).

5. A seamless steel pipe for boilers according to claim 1, characterized in that: The inner wall of the protective shell (8) is provided with a plurality of circumferentially distributed arc-shaped grooves (11). The positions of the arc-shaped grooves (11) correspond to the distribution positions of the elastic support members (9), and the depth of the arc-shaped grooves (11) is one-third to one-half of the wall thickness of the protective shell (8).

6. A seamless steel pipe for boilers according to claim 1, characterized in that: The vent (10) is elliptical in shape, with its major axis parallel to the axial direction of the protective shell (8) and its minor axis parallel to the radial direction of the protective shell (8). The length of the major axis of the vent (10) is one-tenth to one-eighth of the outer diameter of the protective shell (8), and the length of the minor axis is one-twentieth to one-fifteenth of the outer diameter of the protective shell (8).

7. A seamless steel pipe for boilers according to claim 1, characterized in that: The pipe body (1) is provided with flanges (12) at both ends. Multiple evenly distributed mounting holes are provided on the outer edge of the flange (12). The diameter of the mounting holes is 10 mm to 15 mm. The distance between adjacent mounting holes is one-sixth to one-fifth of the outer diameter of the flange (12). A sealing ring groove is provided on the inner side of the flange (12). A high-temperature resistant sealing ring is embedded in the sealing ring groove.

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